[Intravenous infusion of methylene blue to visualize the ureter in laparoscopic colorectal surgery].

Objective: Intraoperative localization of the ureter can contribute to accurate dissection and minimize ureteral injury in colorectal surgery. We aim to summarize a single center's experience of fluorescence ureteral visualization using methylene blue (MB) and explore its visualization efficiency. Methods: This is a descriptive case-series-study. Clinical data of patients who had undergone laparoscopic colorectal surgery and fluorescence visualization of the ureter in the Gastrointestinal Surgery Department of Guangdong Provincial People's Hospital from March 2022 to May 2022 were retrospectively collected. Patients with incomplete surgery videos, renal insufficiency, or allergic reactions were excluded. MB was infused with 0.9% NaCl at 1.0 mg/kg in 100 mL of normal saline for 5 to 15 minutes during laparoscopic exploration. Imaging was performed using a device developed in-house by OptoMedic (Guangdong, China) that operates at 660nm to achieve excitation of MB. Clinical information, MB dosage, rate of successful fluorescence, time to fluorescence, operation time, blood loss, intraoperative blood oxygen levels, pathological staging, changes in renal function, and post-operative complications were retrospectively analyzed. Results: The study cohort comprised 27 patients (24 men and 3 women) with an average age of (60.25±16.95) years and an average body mass index of (21.72±3.42) kg/m2. The dosage of MB was 0.3-1.0 mg/kg and the infusion time was 5-15 minutes. Fluorescence signals were detected in all patients. The median time to signal detection was 20 (range, 10 to 40) minutes after MB infusion. The range of intraoperative blood oxygen fluctuation averaged 2.5% (range, 0 to 7.0%). The median change in creatine concentration was -1.3 (range, -17.2 to 29.2) µmol/L. No patients had complications associated with use of MB. Fluorescence visualization of the ureter was very valuable clinically in two patients (thick mesentery, stage T4). Conclusion: MB is a safe and effective means of visualizing the ureter by fluorescence during laparoscopic colorectal surgery, especially when the procedure is difficult. MB in a dosage of less than 1 mg/kg can slowly infused for more than 5 minutes during laparoscopic exploration. During the infusion, attention must be paid to blood oxygen fluctuations.目的： 输尿管的术中定位可协助结直肠外科的精准层面解剖，避免损伤。本研究旨在总结单中心使用亚甲蓝溶液静脉滴注用于腹腔镜结直肠手术中输尿管荧光显影的经验，探究其显影效果。 方法： 采用描述性病例系列研究方法。回顾性收集2022年3月至2022年5月广东省人民医院胃肠外科使用亚甲蓝溶液静脉滴注用于腹腔镜下结直肠外科术中输尿管显影的病例资料，排除手术录像不完整、肾功能不全及存在过敏反应的患者。亚甲蓝的剂量1.0 mg/kg以内，以100 ml 0.9%氯化钠注射液稀释亚甲蓝至目标剂量，在腹腔镜探查的同时，静脉缓慢滴注亚甲蓝溶液，5~15 min完成滴注。使用内部腹腔镜荧光设备，光源模块采用660 nm作为临床药品亚甲蓝的激发光。观察记录临床信息、亚甲蓝用量、显影率、荧光增益、滴注亚甲蓝溶液后的输尿管开始显影时间、围手术期及手术信息（包括手术时间、出血量、术中血氧变化、术后分期、围手术期肾功能变化及并发症发生情况等）。 结果： 共27例使用亚甲蓝溶液用于腹腔镜下结直肠外科术中输尿管显影的患者被纳入本研究，其中男性24例，女性3例，年龄（60.2±17.0）岁，中位年龄63岁，体质指数（21.7±3.4）kg/m2。亚甲蓝使用剂量为0.3~1.0 mg/kg，滴注时间为5~15 min，显影率为100%，在滴注完亚甲蓝溶液后，观察到双侧输尿管显影中位时间为20（10~40）min。术中中位血氧波动范围2.5（0~7.0）%。全组患者术前、术后肌酐水平变化中位值为-1.3（-17.2~29.2）μmol/L。全组均未发现与使用亚甲蓝溶液相关的并发症。该显影技术在2例困难患者（系膜肥厚、T4期）中体现了较高的应用价值。 结论： 使用亚甲蓝荧光腹腔镜用于结直肠外科术中输尿管显影是安全有效的，尤其是对于困难病例而言。本中心的使用经验是在腹腔镜探查开始时经静脉缓慢滴注亚甲蓝溶液，剂量在1 mg/kg以内，滴注时间≥5 min，期间注意观察血氧变化。.